Gasification-combined power plant

Abstract

The gasification-combined power plant of the present invention has a structure wherein a fuel gas is generated by partially oxidizing a carbon-containing fuel 2 with an oxygen-containing gas 3 in the gasification apparatus 1, the sensible heat of the fuel gas is recovered by the heat exchanger 4, char and dust are removed from the fuel gas by the dust collector 5, trace gas components, such as H 2 S and NH 3 , are simultaneously removed from the waste gas by the gas separation apparatus 6 based on dry physical adsorption of these components (for example, by a pressure swing adsorption method), the thus separated and removed gas containing high concentrations of trace gas components, such as H 2 S and NH 3 , is denitrated and desulfurized by the gas disposal apparatus 7 and then is discharged from the chimney 13 into the atmosphere. With the simultaneous removal of the trace gas components at a high temperature from the fuel gas produced by the gasification apparatus, this plant simultaneously achieves both a high heat efficiency for the gasification-combined power plant as a whole and the reduction of sulfur oxides and nitrogen oxides in the combustion waste gas from the gas turbine.

We claim: 
     
       1. A gasification-combined power plant which comprises: a gasification apparatus for partially oxidizing a carbon-containing fuel with an oxygen-containing gas at a high temperature and under a high pressure;   a gas turbine driven by combustion of a high temperature fuel gas generated in said gasification apparatus; an exhaust heat recovery boiler for recovering heat from a high-temperature gas at an outlet of said gas turbine;   a steam turbine driven by steam produced by heat recovered respectively at said gasification apparatus and said exhaust heat recovery boiler;   a gas clean-up apparatus for purifying at a high temperature the high-temperature fuel gas generated by said gasification apparatus, said gas cleanup apparatus being positioned downstream from said gasification apparatus; a dust collector for removing char and dust from the fuel gas; and   a gas separation apparatus positioned downstream from the dust collector for removing substantially all of the trace gas components from the fuel gas at the same time by way of dry physical adsorption wherein the dry physical adsorption is carried out with a pressure swing adsorption procedure consisting of adsorbing trace gas components adsorbed by the adsorbent by increasing the pressure conditions at the gasification, apparatus, and desorbing and removing the trace gas components from the adsorbent by reducing the pressure, said gas separation apparatus comprising a plurality of adsorption towers containing an adsorbent which is capable of selectively adsorbing trace components from the fuel gas, conduit means for introducing fuel gas to the adsorption towers, means for removing trace component-free fuel gas from the adsorption towers and introducing the removed trace component-free fuel gas to a combustor for the turbine, means to remove trace gas components desorbed from the adsorbent and introduce the removed trace components to a gas disposal apparatus, means for maintaining an elevated pressure in the conduit means and in the adsorption towers, means for withdrawing the fuel gas from the adsorption towers, and means for repeating the physical absorption step by way of pressure increase and the desorption step by way of pressure reduction.   
     
     
       2. A gasification-combined power plant according to claim 1, wherein said gas cleanup apparatus has a gas disposal apparatus for disposing of a gas containing high concentrations of hydrogen sulfide, ammonia and the like which is separated and removed by said gas separation apparatus. 
     
     
       3. A gasification-combined power plant according to claim 2, wherein said gas disposal apparatus comprises a combustion furnace for burning a gas containing high concentrations of hydrogen sulfide, ammonia and the like forwarded from said gas separation apparatus along with air anal an auxiliary fuel supplied thereto, a denitration apparatus and a desulfurization apparatus.